The document discusses Docusaurus, an open source documentation website generator. It summarizes that Docusaurus makes documentation easy by allowing users to write docs in Markdown and generate static HTML files. It also supports features like search, localization, versioning and customization through React extensions. The document demonstrates how large open source projects like React Native and Babel use Docusaurus for their documentation. It previews upcoming changes in Docusaurus 2 that will improve extensibility. The goal of Docusaurus is to encourage open source maintainers to prioritize documentation.